Hack saw



' May 13, 1941 n. E. GOMMEL 2,241,703

HACKSAW Filed my '6, 1939- INVENTOR.

Patented May 13,1941 v I a j 2,241,703

UNITED STATES PATENT OFFICE HACK SAW Dewey E. Gommel, Indianapolis, Ind., assignor to E. C. Atkins and Company, Indianapolis, Ind., a corporation of Indiana Application May 6, 1939, Serial No. 272,063 16 Claims. (01. 29-95) The invention relates to improvements in right angle. Therefore, the face of the tooth is metal cutting saws. machined or otherwise finished of! to bring this One of the objects of the invention is to imface at right angles to the line of cut to thus prove the tooth formation of ahack saw to propresent a square face to the out. Also, as a revide a saw in which the'speed of the cut is masult of the setting of the tooth, the top 6 of the terially increased, the life of the saw is materially tooth would be somewhat angularly disposed and increased, and to provide a hack saw in which in order to overcome this, the top of the tooth is the necessity of frequent sharpening and setmachined or otherwise finished off until the top ting of the teeth of the saw is rendered unnecof the tooth is parallel with the bottom of the essary. 10 out, in order to present-a square tooth surface For the purpose of disclosing the invention, 'to the cut. I have illustrated, in the accompanying draw- In addition to the above construction, I have ing, a segment of a hack saw blade showing a found it advantageous to slightly round the outer number of teeth thereof and in said drawing .top edge 9 of each tooth on a circle having a di- Flg. l is a side elevation of a, portion of a hack ameter of approximately %4 O an it This saw blade; light rounding of the upper edge prevents the Fig. 2 is an enlarged front elevation of a tooth breaking down of this edge, materially increasing of the saw; and the efilciencyof the tooth in cutting.

Fig. 3 is an enlarged plane of a tooth of the Due to the above construction, I have provided saw. in a hack saw extremely deep gullets so curved In the structure illustrated, the teeth l of the as to cause the chip to roll up during the cutting saw, have formed between the same a gullet, 2, operation which rolled chip will be discharged in which gullet is arcuate in form and is approxiits entirety as the saw clears the cut. mately one-half the pitch of the teeth of the Fu h due t e f d that he 8 8111 saw. not as deep as the diameter of the circle on which In the structure illustrated, the depth of the the gulle is d w s the c p wh i r v d gullet is .45 times the pitch of the teeth. The from the tooth curls on this gullet and turns up radius of the circle on which the gullet 2 is at its free end, it will encounter the bottom of formed is .27 times the pitch of the teeth or the the cut, thereby bending the chip down into a diameter of the gullet is approximately one-half tighter curl, th by Providing a p p e in e of the pitch and the peripheral l n th of th gullet for the accommodation of the chip as it gullet is somewhat less than a half circle. The i rem ved fr m the cut by the tooth. While 1 curve 3 of the tooth into which the gullet merges, hav i u d and described my v nt n as has a radius 1.5 times the pitch of the teeth. b i g p u y app t a k s, it The point 4 at which the gullet merges into the will be understood t the invention s a so back curve of the tooth is behind a line drawn applicabletoother types of metal i g saw from the center of the circle on which the back I claim as y invention? curve of the tooth is drawn to the point of the 1. A metal cutting saw blade having circular tooth. Due to this location of the merger point gullets between the teeth substantially one-half of the curve of the gullet and the back curve, 40 the pitch of the teeth, the teeth being curved chips cut by the tooth will freely curl'in the gul-, throughout a portion of their backs on a radius let and there is no hump on the back of the tooth substantially 1.5 times the pitch of the teeth and which would tend to obstruct the movement of merging in the gullets at a point behind a line th chlpfi The back curve radius 3 0f the tooth drawn from the tooth point to the center of the merges into the top 6 of the tooth and the length ircle n which the back curve is drawn. of the top of the tooth is .125 times the pitch. 2. A metal cutting saw blade having curved This top 6 of the tooth is straight and has an gullets between the teeth, having a depth subanzle o 10 degrees, as is the e o e front stantially one-half of thepitch of the teeth, said hook I of the t othgullets merging into a. straight tooth hook havin The tooth is set on a line 8 extending approxisubstantially 10 degree gm, g mately 45 degrees from the vertical line of the 3, A metal cutting saw bmde having curved face of the tooth, which will impart to the tooth gullets between the teeth, having a diameter suba Peculiar Wist- AS a result of e setting n stantially one-half the pitch of the teeth, side the 45 degree angle line, the face of the tooth will gullets merging into a straight hook of the teeth incline at an angle to the C t gre er than a which is substantially at a 10 degree angle and said reversely curved back portion being substantially one and one-half times the pitch of the teeth. a

4. A metal cutting saw blade having a circular gullet, the circle 01' said gullet having a. diameter substantially one-half the pitch of the teeth, a portion of the backs of the teeth being reversely curved on a radius substantially one and onehalf times the pitch oi the teeth and merging into the gullet at a, point behind the line drawn through the center the circle on which the backs of the teeth are drawn and the point of the tooth, said curved portion also merging into a straight back of the tooth approximately .125

times the pitch and extending at a. degree angle.

5. A metal cutting saw blade having circular gullets between the teeth and a portion 01' the backs of the teeth reversely curved, the back or on which the back is curved. 9. A metal cutting saw blade havingcurved guilets between the teeth having a depth subone-haif the pitch stantially' of the teeth, said gullets merging into a hook tooth having an angle less than 15 degrees.

10. A metal drawn.

11. A metal cutting saw blade gullets between the teeth and a with the bottom of the cut.

circles being less than a to the line of the cut.

DEWEY E. GOMMEL. 

